Interlocking closure device

ABSTRACT

A closure device for a thermoplastic bag which includes two opposing, longitudinally extending interlockable male and female fastening strips having respective male and female closure elements or profiles that are deformed to interdigitate and produce an audible clicking sound and or tactile effect that is perceptible to the touch as the closure device is opened and closed. Interdigitation of the two profiles is achieved by cold forming the profiles while interlocked. The shape of the cold form is a stepped deflection of both profiles so that their shapes are generally congruent. The stepped deflections provide a change in the occlusion and peel force of the interlocking closure device thereby resulting in an audible clicking or popping sound as the closure device is opened and closed and a tactile effect that is perceptible to the touch as the closure device is closed.

FIELD OF THE INVENTION

The present invention relates generally to interlocking closure devicesfor thermoplastic storage bags, and more particularly, to aninterlocking closure device which produces an audible sound when theclosure device is being open or closed. Further, the closure deviceprovides a vibration or bumpy feel, which is tactile and readilyperceptible to the touch when the closure device is closed.

BACKGROUND OF THE INVENTION

The use of closure devices for fastening storage containers, includingplastic bags, is generally known. Furthermore, the manufacture ofclosure devices made of plastic materials is generally known to thoseskilled the in the art, as demonstrated by the numerous patents in thisarea.

A particularly well-known use for closure devices is in connection withflexible storage containers, such as plastic bags. In some instances,the closure device and the associated container are formed fromthermoplastic materials, and the closure device and the sidewalls of thecontainer are integrally formed by extrusion as a single piece.Alternatively, the closure device and sidewall of the container may beformed as separate pieces and then connected by heat sealing or anyother suitable connecting process. In either event, such closure devicesare particularly useful in providing closure means for retaining matterwithin the bag.

Conventional closure devices typically utilize a thermoplastic zipper inthe form of mating fastening strips or closure elements, which are usedto selectively seal the bag. The fastening strips comprise interlockablemale and female profiles. With such closure devices, however, it isoften difficult to determine whether the fastening strips are fullyoccluded. The problem addressed by the present invention pertains to thedetermination of closure or nonclosure of the zipper of a reclosablethermoplastic bag.

One technique for aiding in the determination of the state of zipper isto utilize a zipper that imparts a visual color change upon closure.Different colors may be utilized in each of the opposing zipper profilesto produce a third distinct color when interlocked. Zippers utilizingsuch a color change are seen in U.S. Pat. Nos. 4,186,786 and 4,285,105.

It is well understood that all thermoplastic zippers have an occlusionand peel force. It is also known that a desired audible and/or tactileeffect can be achieved during opening or closure of the zipper bychanging the occlusion and peel force along the length of the zipper.One technique for changing this force is to remove portions of one orboth of the male and female zipper profiles such that there is adiscontinuity in structure in those portions of the opposing profileswhich contact each other upon interlockment of the zipper. Examples ofzippers having closure profiles with portions removed are disclosed inU.S. Pat. No. 5,070,584 to Dais et al. and U.S. Pat. No. 5,647,100 toPorchia et al.

In U.S. Pat. No. 5,070,584, at least one of the zipper profiles includesindentions within and intermittently along its length along a surface ofit adjacent a portion of the opposing profile. The indentions arepresent in and along a part of the zipper profile interlockable with apart of the opposing zipper profile wherein both of the interlockableparts are longitudinally extending. The indentions and the surfaceswhich define or bound the indentions of the part of the zipper profileare adjacent the part of the opposing zipper profile with which it isinterlocked. This patent further discloses that the part of the zipperprofile having indentions therein is substantially free ofinterdigitation with the part of the opposing zipper profile with whichit is interlockable. According to this patent document, being“substantially free of interdigitation” means that the cavities definedby the indentions within the part are substantially free of intrusion byportions of the part of the opposing profile. The indentions in thebulbous head of the male closure profile provide the structuraldiscontinuity in the region of interlocking contact with the femaleclosure profile that creates the desired audible clicking sound and/ortactile effect.

In accordance with the preferred method of making the above-describedaudible/tactile zippers, a rotary punch apparatus is used to laterallypunch out segments of the bulbous head of the male closure profile toform indentations along its length. The punching is lateral as it occursin a direction that is perpendicular to the extension of the bulboushead. In the final assembly of the zipper bag, the interlocking male andfemale profiles are then brought together in a separate step beforebeing attached to the opposing bag side panels. A method of making anaudible/tactile zipper closure wherein the interlocking closure profilesare made structurally discontinuous while interlocked to each otherwould be desirable as it would reduce the number of steps in the finalassembly of the zipper bag.

The punching technique described above also generally requires carefulattention to profile positioning and alignment of the zipper profilethrough the deforming apparatus to ensure against removal of too muchprofile material, which otherwise results in the increased likelihood orincidence of liquid leakage through the interlocked zipper. The zipperprofiles disclosed in the '584 patent have enjoyed much commercialsuccess. However, there still exists a need for alternative and improvedthermoplastic closure members that impart a vibration perceptible to thetouch, and emanate an audible clicking sound along the closure member'slength when being closed or interlocked so that the fact of closure canbe confirmed by a nonvisual means, i.e., by sound and feel.

Accordingly, it is desired to provide a reclosable bag having animproved closure member that imparts a vibration perceptible to thetouch, and, further preferably, emanates an audible clicking soundcontinually along the closure member from end to end; and it is desiredto provide a method for production of the reclosable bag whereinmaterial is not removed from the closure region such that leakresistance through the closure is improved.

SUMMARY OF THE INVENTION

The present invention provides a closure device for a thermoplastic bagwhich includes two opposing, longitudinally extending interlockable maleand female fastening strips having respective male and female closureelements or profiles that are deformed to interdigitate and produce anaudible clicking sound and or tactile effect that is perceptible to thetouch as the closure device is opened and closed. Interdigitation of thetwo profiles is achieved by cold forming the profiles while interlocked.The shape of the cold form is a stepped deflection of both profiles sothat their shapes are generally congruent. The stepped deflectionsprovide a change in the occlusion and peel force of the interlockingclosure device thereby resulting in an audible clicking or popping soundas the closure device is opened and closed and a tactile effect that isperceptible to the touch as the closure device is closed.

In accordance with an advantageous aspect of the invention, thecompressive force across the stepped deflection is graduated such thatthe greatest amount of compression is experienced at the outermost oruppermost portion of the closure profiles. In this way, leak resistancethrough the closure device is improved and the desired audible and/ortactile effects are still achieved.

Methods and apparatus which incorporate the features described above andwhich are effective to function as described above constitute further,specific objects of the invention. Other objects and advantages of theinvention will become apparent upon reading the following descriptionand upon reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this invention reference should nowbe had to the embodiments illustrated in greater detail in theaccompanying drawings and described below by ways of examples of theinvention. In the drawings:

FIG. 1 is a perspective view of a container in the form of athermoplastic bag having an interlocking closure device in accordancewith the present invention;

FIG. 2 is an enlarged cross-sectional view taken along reference line2—2 of FIG. 1;

FIG. 3 is an enlarged cross-sectional view taken along reference line3—3 of FIG. 1;

FIG. 4 is an enlarged isometric fragmentary view partly in section ofthe female closure element of the interlocking closure device shown inFIG. 1;

FIG. 5 is an enlarged isometric fragmentary view partly in section ofthe male closure element of the interlocking closure device shown inFIG. 1;

FIG. 6 is an enlarged isometric fragmentary view partly in section,which shows the female closure element of FIG. 4 and the male closureelement of FIG. 5 being interlocked by hand;

FIG. 7 is an enlarged cross-sectional view taken along reference line7—7 of FIG. 1;

FIG. 8 is a enlarged cross-sectional view similar to that of FIG. 2 onlyof a second embodiment of the interlocking closure device of FIG. 1 inaccordance with the present invention;

FIG. 9 is an enlarged isometric perspective view partly in section ofthe male closure element of the interlocking closure device of FIG. 8;

FIG. 10 is an enlarged isometric perspective view partly in section ofthe female closure element of the interlocking closure device of FIG. 8;

FIG. 11 is an isometric view of a deforming apparatus according to thepresent invention wherein a mating pair of interlocked closure elementsare being processed therethrough and shown fragmentarily;

FIG. 12 is a greatly enlarged side view of a tooth of a rotary member ofthe deforming apparatus of FIG. 11;

FIG. 13 is a greatly enlarged fragmentary cross-sectional view takenalong line 13—13 of FIG. 12;

FIG. 14 is an enlarged side view of the interlocked closure profilesbeing processed through the deforming apparatus of FIG. 11;

FIG. 15 is an enlarged side view of interlocked closure profiles beingprocessed through a deforming apparatus constructed in accordance with atooth-to-space embodiment of the present invention;

FIG. 16 is an enlarged isometric fragmentary view partly in section ofthe female closure element of the interlocking closure profile upondeformation by the tooth-to-space deforming apparatus of FIG. 15;

FIG. 17 is an enlarged isometric fragmentary view partly in section ofthe male closure element of the interlocking closure profile upondeformation by the tooth-to-space deforming apparatus of FIG. 15;

FIG. 18 is an enlarged side view of interlocked closure profiles beingprocessed through a deforming apparatus constructed in accordance with atooth-to-tooth embodiment of the present invention;

FIG. 19 is an enlarged isometric fragmentary view partly in section ofthe female closure element of the interlocking closure profile upondeformation by the tooth-to-tooth deforming apparatus of FIG. 18; and

FIG. 20 is an enlarged isometric fragmentary view partly in section ofthe male closure element of the interlocking closure profile upondeformation by the tooth-to-tooth deforming apparatus of FIG. 18.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides interlocking closure devices withspecially formed mating closure elements that produce an audible soundand/or provide a tactile sensation upon occlusion and deocclusion of theclosure elements. As used herein and as generally understood in the art,the terms “male” and “female” closure elements refer to closure elementswherein the element that interlocks into the other closure element isreferred to as the “male closure element” and the other element isreferred to as the “female closure element.” In addition, the terms“outermost” and/or “uppermost” webs refer to leg or stem portions of themale and female closure elements located nearest to the open top end ofthe bag. Conversely, the terms “innermost” and/or “lowermost” webs referto leg or stem portions of the male and female closure elements locatednearest to the closed bottom end portion of the bag.

FIG. 1 illustrates a container according to the present invention in theform of a thermoplastic bag 120 having a sealable interlocking closuredevice 121. The bag 120 includes sidewalls 122 joined at seams 125 toform a compartment sealable by means of the closure device 121. Thesidewalls 122 extend beyond the closure device 121 to provide mouthportions 124 to simplify opening of the closure device 121. The closuredevice 121 or “zipper”, a common term of art by which the closure deviceis also known as, is preferably continuous in length across the open topof the bag 120.

Generally, the closure device 121 comprises fastening strips arranged tobe interlocked over a predetermined length. The fastening strips includemale and female closure elements or profiles that interlock andinterdigitate with each other. Typically the closure force of theclosure elements is cycled intermittently over the length of the closuredevice between a low closure force and a high closure force, with thechanges in closure force being produced in turn by making a series ofintermittent and substantially congruent structural discontinuities ineach of the contact surfaces of the male and female closure elementswhile interlocked to each other. These structural discontinuities aremanifest in the form of first series of valleys or indentations in thecontact side of one of the male or female closure elements and a secondseries of peaks or protrusions in the contact side of the opposing maleor female closure element. The process for forming the structuraldiscontinuities in the two parts is preferably done by cold forming aseries of stepped deflections in the two pieces while interlocked suchthat the peaks of one closure element are in substantially congruent andinterdigitating relation with the valleys of the second closure element.Preferably, the peaks are slightly out of phase with the valleys toprovide a desired degree of interference contact therebetween. It is theinterference contact that produces the audible popping or clicking soundand tactile sensation when the closure elements are occluded anddeoccluded. The stepped deflections produced by the cold form processare indicated generally by reference numeral 126.

More specifically, in accordance with one embodiment of the presentinvention, there is shown in FIG. 2 a cross section view through theclosure device 121 at a region free of any stepped deflection. Theclosure device comprises male and female fastening strips 130, 131. Thefemale fastening strip 131 includes a female closure element 134. Themale fastening strip 130 comprises a male closure element 136 forengaging the female closure element 134.

The fastening strips 130, 131 have a longitudinal X axis 102 and atransverse Y axis 104 which is perpendicular to the longitudinal X axis102. Also, the fastening strips have a vertical Z axis 106 which isperpendicular to the longitudinal X axis 102 and the vertical Z axis isperpendicular to the transverse Y axis 104.

The female closure element 134 may include a base portion 138 and mayinclude a pair of spaced-apart parallely disposed webs 140, 141extending from the base portion 138. The webs 140, 141 may includefemale hook closure portions 142, 144 extending from the webs 140, 141respectively, and facing towards each other. The female hook portions142, 144 may include guide surfaces 146, 147 which serve to guide thehook portions 142, 144 for occluding with the male hook portions of amating closure element. The male closure element 136 may include a baseportion and may include a pair of spaced-apart, parallely disposed webs150, 151 extending from the base portion 148. The webs 150, 151 mayinclude male hook closure portions 152, 154 extending from the webs 150,151 respectively and facing away from each other. The male hook portions152, 154 may include guide surfaces 145, 155, which generally serve toguide the hook portions 152, 154 for occlusion with the female hookportions 142, 144 of the mating female closure element. The guidesurface 145 may also have a rounded crown surface. In addition, the hookportions may be designed so that the hook portions 144, 154 adjacent theinterior of the container provide a greater resistance to opening of theclosure device. The male fastening strip may include a pair of malewings 137 spaced-apart on the male fastening strip on each side of themale closure element 136. The male wings 137 are flexible and extendfrom the base of the fastening strip. In accordance with a preferredembodiment, each wing terminates in an end portion 143 which projectsoutwardly from the wing 137. Alternatively, the end portions 143 do notproject outwardly as shown in FIGS. 2 and 3 but instead are aligned withthe wings 137 as shown in FIG. 5. The female fastening strip 131 mayalso include a color change enhancement member 156. In similar fashionto the male fastening strip 130, the female fastening strip 131 may beprovided with a pair of female wings (not shown) spaced-apart on thefemale fastening strip on each side of the female closure element 134.

FIG. 3 is a cross section view of the closure device showing an occludedstate of the closure elements 134, 136 through a region corresponding toa stepped deflection 126. In this view, the outermost or uppermost webs140 and 150 of the fastening strips 131 and 130, respectively, arecompressed as a result of the cold form stepped deflection 126 (see FIG.1). The compression of webs 140 and 150 is concentrated generally alongthe transverse Y axis 104. Although not readily apparent in this view,the innermost or lowermost webs 141 and 151 of respective fasteningstrips 131 and 130 may also be compressed.

Closure devices of the present invention preferably are substantiallyleakproof. For example, surfaces of the interlockable male and femaleclosure elements preferably form a contiguous or snug fit with eachother along the entire length of the closure device. In the preferredembodiment only the outer most webs 140 and 150 are compressed as thissignificantly minimizes the possibility of leakage through the closuredevice.

The amount of compression imparted to the webs 140, 150, 141, 151 willdepend ultimately on how accurate the deforming apparatus is setinitially. The deforming apparatus and method of producing the steppeddeflections with selectable compression force is discussed in moredetail below with reference to FIGS. 11-14.

FIG. 4 shows a perspective view of a portion of the female closureelement 134. The stepped deflections 126 imparted to the interlockingclosure device 121 result in a series of intermittent valleys orindentations 126 a being formed in the closure contact area of theoutermost female hook closure portion 142. The portions of the web 140underlying the valleys 126 a are compressed generally along thetransverse Y axis 104. Note, the compression is more readily apparent inFIG. 3. Arrow D generally designates the direction of the applieddeflection force in this Figure (FIG. 4) and also in FIGS. 5 and 9-10.

FIG. 5 shows a perspective view of a portion of the male closure element136. The stepped deflections 126 imparted to the interlocking closuredevice 121 result in a series of intermittent peaks or protrusions 126 bbeing formed in the closure contact area of the outermost male hookclosure portion 154. The portions of the web 151 underlying the peaks126 b are compressed.

As noted above, for best leakproofing results it is preferred that thecompression be concentrated to the outermost or uppermost webs 151 and140 of the respective male and female closure elements 136 and 134. Theoutermost or upper most wing 137 of the male closure element 136 mayalso be compressed. The amount of compression on the wing 137 willdepend on how tall and how straight up the wing 137 extends initially.In other words, there would be no compression if the wing tip hasnothing to abut against during cold forming of the stepped deflectionsIn this embodiment, any compression of the wing 137 will not make anyappreciable contribution to the desired audible/tactile effect. However,in an alternate embodiment of the invention wherein the female fasteningstrip 131 is provided with a pair of outside wings as mentioned above,the female wings may be positioned to contact a respective outside wing137 of the male fastening strip 130 when the fastening strips areinterlocked. In this embodiment, the step of forming the congruentseries of stepped deflections in the interlocked closure elements mayinduce some compression in one or both of the outer most wing(s) of themale and female closure elements since the wing tip(s) would now have apotential abutment surface against which to act.

FIG. 6 shows closure device 121 of one embodiment wherein the male andfemale fastening strips 130, 131 are being interlocked by handmanipulation in the form of thumb 158.

FIG. 7 illustrates the substantially congruent and interdigitatingrelationship between the respective series of stepped deflections of themale and female closure elements wherein the formed peaks 126 b of themale closure element 136 interdigitate within the formed valleys 126 aof the female closure element 134. As noted above, the series of peaks126 b are preferably slightly out of phase with the valleys 126 a of thefemale closure element 134 in order to ensure that a desired amount ofinterference exists between the two structures so that a desired audibleand tactile effect is achieved. The range of interference can beselected to be large or small in order to achieve an audible effect injust one of or both of the opening and closing directions of theinterlocking closure device.

Another embodiment of the present invention is seen in interlockingclosure device 221 in FIGS. 8-10. Closure device 221 is an example of a“rib and groove” type zipper closure and comprises opposinglongitudinally extending interlockable rib profile 240 and grooveprofile 241. Rib profile 240 defines a head 246, a stem 242, and one ormore ribs 244. Stem 242 and ribs 244 are essentially continuous, andlongitudinally extend along profile 240. Head 246 extends longitudinallyalong profile 240. Rib profile 240 is further defined by a first seriesof intermittent and preferably alternating stepped deflections. In thisexample, the stepped deflections are in the form of peaks or protrusions348 a on the rib profile 240. Head 246 is generally bulbous in shape inthe regions between the peaks 348 a and is slightly more elongate anddistorted in regions of the deflected peaks 348 a resulting instructural discontinuity along profile 240. The term “bulbous” in thisspecification includes not only round but also generally arrow-like ortriangular-shaped as is commonly seen in the prior art. Stem 242 extendsfrom rib base 240 a to define head 246 at its free end. Head 246includes oppositely disposed outwardly extending hooks 248. Head 246constitutes a longitudinally extending part of profile 240 interlockablewith an essentially continuous and longitudinally extending part ofgroove profile 241 constituting groove arms 247. Groove arms 247 extendfrom groove base 241 a of groove profile 241. Groove arms 247 straddlehead 246 when profiles 240 and 241 are interlocked, and define hooks 249at their free ends to be engagable and interlockingly coextensive withthe hooks 248 of head 246. Groove profile 241 is further defined by asecond series of intermittent and preferably alternating steppeddeflections in the formed of valleys or indentions 348 b. Preferably,the peaks 348 a of the bulbous head 246 of the rib profile 240 are insubstantially congruent and interdigitating relation with valleys 348 bof the groove profile 241. The direction of applied force in creatingthe stepped deflections on the two parts in indicated by arrow D. In analternative arrangement, the direction of applied force on the two partsis reversed such that the groove profile is defined by a series of peaksor protuberances and the bulbous head of the rib profile is defined by aseries of valleys or indentations.

The terms “rib profile” and “groove profile” are used as terms ofconvenience to describe opposing interlockable male and female zipperprofiles, and are not to be construed as limiting.

Although several interlocking fastening strip embodiments have beenspecifically described and illustrated herein, it will be readilyappreciated by those skilled in the art that other kinds, types, orforms of fastening strips can alternatively be used without departingfrom the scope or spirit of the present invention. The disclosedembodiments of the present invention are not to be construed aslimiting. The art is replete with interlocking closure devices, zippers,and reclosable fasteners of different structures and configurationsadaptable to thermoplastic bags. Examples of this art are seen in U.S.Pat. No. 4,363,345, U.S. Pat. No. 4,561,109, and U.S. Pat. No.4,528,224. Prior art zipper structures can readily be modified inaccordance with the present invention to form a zipper having thedesired audible clicking and/or vibratory and bumpy feel which istactile and perceptible to the touch.

When the fastening strips are used in a sealable bag, the fasteningstrips and the films that form the body of the bag may be convenientlymanufactured from heat sealable material. In this way, the bag may beeconomically formed by using an aforementioned thermoplastic materialand by heat sealing the fastening strips to the bag. For example, thebag may be made from a mixture of high pressure, low-densitypolyethylene and linear, low-density polyethylene.

The fastening strips may be manufactured by extrusion through a die orother known methods and may be formed from any suitable thermoplasticmaterial including, for example, polyethylene, polypropylene, nylon, orthe like, or from a combination thereof. Thus, resins or mixtures ofresins such as high-density polyethylene, medium-density polyethylene,and low-density polyethylene may be employed to prepare the interlockingfastening strips. For example, the closure device may be manufactured asindividual fastening strips for later attachment to the bag or may bemanufactured integrally with the bag. In addition, the fastening stripsmay be manufactured with or without flange portions on one or both ofthe fastening strips depending upon the intended use of the fasteningstrips or expected additional manufacturing operations.

Generally, the fastening strips can be manufactured in a variety offorms to suit the intended use. The fastening strips may be integrallyformed on the opposing sidewalls of the container or bag, or connectedto the container by the use of any of several known methods. Forexample, a thermoelectric device may be applied to a film in contactwith the flange portion of the fastening strips or the base portion offastening strips having no flange portion, to cause a transfer of heatthrough the film to produce melting at the interface of the film and aflange portion or base portion of the fastening strips. Suitablethermoelectric devices include heated rotary discs, traveling heaterbands, resistance-heated slide wires, and the like. The connectionbetween the film and the fastening strips may also be established by theuse of hot melt adhesives, hot jets of air to the interface, ultrasonicheating, or other known methods. The bonding of the fastening strips tothe film stock may be carried out either before or after the film isU-folded to form the bag. In any event, such bonding may be done priorto side sealing the bag at the edges by conventional thermal cutting. Inaddition, the first and second fastening strips may be positioned onopposite sides of the film. Such an embodiment would be suited forwrapping an object or a collection of objects such as wires. The firstand second fastening strips should usually be positioned on the film ina generally parallel relationship with respect to each other, althoughthis will depend on the intended use.

The interlocking closure device may be deformed to include the series ofintermittent stepped deflections once the male and female closureelements are interlocked and either before or after the fastening stripsare attached to the bag film stock in the case where the closure deviceis manufactured separately from the bag. In the case where the closuredevice is formed integral with the bag sidewalls, the closure device isdeformed after the male and female closure elements are interlocked.

The means for providing the male and female fastening strips 130, 131preferably comprises an extruder (not shown) and a die means (not shown)to shape the profiles of the male and female closure elements orprofiles of the fastening strips as is commonly known in the art. Themeans for providing the male and female fastening strips may alsocomprise a means for advancing the fastening strips.

A means of deforming the interlocked fastening strips 130, 131 is shownin FIGS. 11 and 14, and is referred to hereafter as deforming apparatus290. The deforming apparatus 290 creates the stepped deflections (i.e.,peaks and valleys) in the areas of contact between the male and femaleclosure elements as shown in FIGS. 4-6 and 9-10 and also the compressionin the web portions underlying the valleys as best shown in FIG. 3.Prior to being deformed, the fastening strips 130, 131 are firstinterlocked. The means for interlocking the opposing male and femalefastening strips may take the form of juxtapositioned closing rollers300, 301 as commonly known in the art. The opposing male and femaleclosure elements or profiles of the fastening strips are interlocked asthey pass between the closing rollers 300, 301. The opposing closureelements or profiles may also be interlocked by hand as seen in FIG. 6.

Means for advancing the fastening strips 130, 131 preferably comprise apair of juxtapositioned deforming wheels 302, 303 that are driven byrespective rotary members 304 and 305, which act to pull the interlockedfastening strips therebetween by compression as the members 304 And 305are rotated. Rotary members 304 and 305 may be rotated by mechanical orelectromechanical means known in the art (not shown). Other conceivablemeans for advancing the interlocked fastening strips 130, 131 includemechanized feed and takeup rolls (not shown).

The deforming wheels 302, 303 each include a plurality of radiallysituated, outwardly projecting teeth 306 and 307, respectively, that arebrought into contact with the backsides (i.e., the side of the fasteningstrip opposite the closure element) of the respective fastening strips130, 131. The rotary members 304, 305 are positioned with respect toeach other so that the teeth 306, 307 of each are spaced apart and arein generally interdigitating alignment with a slight overlap as members304, 305 are rotated in opposite directions. The deforming wheels 302,303 are staggered such that the individual teeth 306 of wheel 302contact and deform the backside of fastening strip 130 in a slightoffset overlapping alternating fashion with respect to the point ofcontact and deformation of the back side of fastening strips 131 asproduced by teeth 307 of wheel 303. Preferably, the contact of anddeformation caused by the teeth 306, 307 on the respective backsides offastening strips 130, 131 is done without excising any appreciableamount of material. The alternating and staggered contact of the twosets of teeth 307 and 307 on the respective backsides of the interlockedfastening strips 130, 131 combined to produce the stepped deflections138 (i.e., the generally congruent peaks and valleys) described above.The alternating slight overlapping pattern of stepped deflections formedin the interlocked fastening strips 130, 131 by the deforming apparatus207 is best seen in FIG. 14. In the preferred embodiment, the timing isvaried to create a certain amount of interference overlap between thecongruently formed stepped deflections in the two fastening strips. Byadjusting the series of valleys formed in one part to be more or lessslightly out of phase with the congruently formed series of peaks in theother part, the loudness and/or tactile effect can be emphasized orde-emphasized accordingly.

In accordance with a preferred embodiment, the fastening strips 130, 131are cold deformed by the teeth 306, 307. That is, the fastening strips130, 131 are sufficiently cooled to a point upon exiting the extrudersuch that they are no longer in a molten or semi molten state prior toentering the deforming wheels 302, 303.

Teeth 306, 307 are spaced about deforming wheels 302 and 303 in a pitchcorresponding to the desired frequency of stepped deformations on therespective fastening strips 130, 131. The tooth configuration of andspacing between the teeth 306, 307 may be varied as desired to produce adesired audible and tactile effect. For example, it may be desired tohave a soft clicking sound at the beginning of the bag and a louderclicking sound at the closing end of the bag. Distinctive and/orrepeating audible and/or tactile patterns can also be generated byselectively varying the tooth spacing and tooth configuration. As seenin FIG. 12, the sides of the teeth 306 and 307 may be tapered, with apreferred angle of taper of between 2 to 5 degrees.

The fastening strip contacting surfaces of the teeth 306, 306 arepreferably tapered in the transverse direction (i.e., parallel to thevertical Z axis 106 of the fastening strips) as shown by angle θ in FIG.13, with a preferred angle falling with in a range of 8 to 12 degrees.The preferred gap or distance spacing between the gear teeth of opposingdeforming wheels in an offset position is 0.010 inch to 0.030 inch. Thepreferred stitch (stitch being defined as the tooth point to tooth pointspacing as seen in FIG. 14) is 0.015 inch to 0.020 inch. The selectedangle of taper for the gear teeth sides and the selected angle of taperfor the gear teeth contacting surfaces, in combination with the selectedtooth height, gap, and provide flexibility in how the compressive forceis to be distributed across the closure elements. As noted above, forinterlocking closure devices and, in particular, closure devices havingclosure elements or profiles arranged in U shaped configuration as shownin FIGS. 2-3, it has been found that leak resistance through the closuredevice is improved where compression is focused only on the outer mostweb portions 140, 150 of the respective male and female closure elements136, 134. In accordance with an alternative method for applying aselective compressive force to only the outer most web portions of theoccluded fastening strips, rather than tapering the gear teeth, the axisof rotation of one of the deforming wheels may by titled at an anglewith respect to the axis of rotation of the juxtaposed deforming wheel.The end result being the same, that is the gear teeth selectively applymore compressive force to the outer most web portions of the occludedfastening strips.

In accordance with an advantageous aspect of the invention, thedeforming wheel apparatus may be readily incorporated within an existinginterlocking closure bag production line without substantialmodification to the existing line.

FIG. 15 illustrates another embodiment of a “tooth to space” deformingapparatus 390, which is similar in most respects to the deformingapparatus 290 discussed above in connection with FIGS. 11-14, exceptthat the gear teeth 407, 407 of respective deforming wheels 402, 403 areoffset to a much greater extent such that the gear teeth 406 ofdeforming wheel 402 align with corresponding valleys 408 of deformingwheel 403. Similarly, gear teeth 407 of deforming wheel 403 align withcorresponding valleys 405 of deforming wheel 402. The preferredpenetration of the respective gear teeth of the tooth-to-space deformingapparatus is 0.05 inch to 0.10 inch.

FIGS. 16 and 17 show perspective views of portions of the female closureelement 434 and male closure element 436 after undergoing deformation bythe “tooth to space” deforming apparatus 390 of FIG. 15. In thisembodiment, deformation of the profile pieces occurs along both thetransverse Y-axis 104 and the vertical Z-axis 106. In FIG. 16, thedeformation induced by the tooth to space deforming apparatus 390results in a compression of the webs 440, 441 in the transverse Y-axis104 and the formation of valleys 426 a and peaks 426 b in respectivehook closure portions 442, 444. In addition, the deformation causes thewebs 440, 441 to spread or deflect outward along the vertical Z-axis106. The outward spreading or deflection means that the upper oroutermost web 440 leans towards to the top or open end of the bag andthe inner or lowermost web 441 leans towards the bottom or closed end ofthe bag. In other words, as used herein in connection with thedescription of the “tooth-to-space” embodiment the term “outwardspreading” refers to the spreading or bending of the spaced apart websthat occurs relative to the longitudinal center axis of the closureelement. Thus the valleys 426 a formed in the hook portions 442, 444have a deformation component along both the transverse Y-axis 104 andthe vertical Z-axis 106.

Similarly, in FIG. 17 the tooth-to-space deformation results in acompression of the webs 450, 451 in the transverse Y-axis 104 and theformation of valleys 426 a and peaks 426 b in respective hook closureportions 452, 454. In addition, the deformation causes the outer web 451to spread outward or deflect in the same vertical Z-directions alongwith corresponding outer web 440 of the female closure element 434(i.e., the outer web 451 is deflected towards the top or open end of thebag). Inner web 450 spreads outwardly or deflects in the vertical Zdirection along with corresponding inner web 441 of the female closureelement 434 (i.e., the inner web 450 is deflected towards the bottom orclosed end of the bag). The wings 437 (depending on their dimension) mayalso experience some compression in the transverse Y direction and someoutward spreading along the vertical Z direction.

FIG. 18 illustrates another embodiment of a “tooth-to-tooth” deformingapparatus 490, which is similar in most respects to the deformingapparatus 290 discussed above in connection with FIGS. 11-14, exceptthat the gear teeth 506, 507 of respective deforming wheels 502, 503 arealigned to face one another with no appreciable offset. The preferredgap or distance spacing between opposing gear teeth is 0.025 inch to0.050 inch.

FIGS. 19 and 20 show perspective views of portions of the female closureelement 534 and male closure element 536 after undergoing deformation bythe “tooth to tooth” deforming apparatus 490 of FIG. 18. In thisembodiment, the deformation of the profile pieces occurs mostly alongthe vertical Z-axis 106. In FIG. 19, the deformation induced by thetooth-to-tooth deforming apparatus 490 results in the outward spreadingof the webs 540, 541 along the vertical Z-axis 106. The outwardspreading causes the upper or outermost web 540 to lean towards to theopen end of the bag and the inner or lowermost web 541 leans towards theclosed end of the bag.

Similarly, in FIG. 20 the tooth-to-tooth deformation causes the outerweb 551 to spread outward in the same vertical Z direction along withcorresponding outer web 540 of the female closure element 534. Inner web550 spreads outwardly in the vertical Z direction along withcorresponding inner web 541 of the female closure element 534. The wings537 (depending on their dimension) may also experience some spreading ordeflection in the vertical Z direction.

It is understood that the alternate embodiments described above inconnection with FIGS. 15-20 may also include color change enhancementmembers and the fastening strips may be of different colors in order toeffect a color change when the zipper is occluded. In fact, thealternate embodiments for the closure device disclosed in FIGS. 15-20may include all the same features and have all the same or similaradvantages as discussed above in connection with the embodiments shownin FIGS. 1-14.

From the foregoing it will be understood that modifications andvariations may be effectuated to the disclosed structures—particularlyin light of the foregoing teachings—without departing from the scope orspirit of the present invention. As such, no limitation with respect tothe specific embodiments described and illustrated herein is intended orshould be inferred. On the contrary, it is intended to cover allalternatives, modifications and equivalents as may be included withinthe spirit and scope of the invention as defined by the appended claims.

What is claimed:
 1. A closure device for a reclosable plastic bagcomprising: a first fastening strip; a second fastening strip arrangedto be interlocked over a predetermined longitudinal X axis with saidfirst fastening strip, said fastening strips have a transverse Y axis,said transverse Y axis is perpendicular to said longitudinal X axis,said fastening strips have a vertical Z axis, said vertical Z axis isperpendicular to said longitudinal X axis, said vertical Z axis isperpendicular to said transverse Y axis, said first fastening stripcomprises a first closure element that extends from said first fasteningstrip along the transverse Y axis, said second fastening strip comprisesa second closure element that extends from said second fastening stripalong the transverse Y axis and which engages said first closure elementwhen said fastening strips are occluded, said first and second closureelements having an occlusion and peel force; said first closure elementincluding a first series of intermittent deformations disposed along itslongitudinal X axis, each of said first series of deformations having adeformation component along the transverse Y axis thereby defining areasof compression in the first closure element; said second closure elementincluding a second series of intermittent deformations disposed alongits longitudinal X axis, each of said second series of deformationshaving a deformation component along the transverse Y axis therebydefining areas of compression in the second closure element and saidareas of compression of second series of deformations being insubstantially congruent and interdigitating relation with said areas ofcompression of said first series of deformations when said first andsecond fastening strips arc interlocked such that said occlusion andpeel force is cycled intermittently over the length of the closuredevice.
 2. The invention as in claim 1, wherein: said areas ofcompression of said first series of intermittent deformations comprise aplurality of peaks; and said areas of compression of said second seriesof intermittent deformations comprise a plurality of valleys.
 3. Theinvention as in claim 1 wherein said first closure element comprises arib profile having a longitudinally extending head bulbous in shape andsaid second closure element comprises a longitudinally extending grooveprofile.
 4. A closure device for a reclosable plastic bag comprising:first and second interlocking fastening strips arranged to beinterlocked over a predetermined length, said first fastening stripincludes a first closure element, said second fastening strip includes asecond closure element; said first and second closure elements having anocclusion and peel force; said first closure element having a firstseries of intermittent stepped deflections along its length; said secondclosure element having a second series of intermittent steppeddeflections along its length, said second series of intermittent steppeddeflections being in substantially congruent and interdigitatingrelation with said first series of intermittent stepped deflections whensaid first and second fastening strips are interlocked such that saidocclusion and peel force is cycled intermittently over the length of theclosure device; and wherein: said first closure clement comprises afirst outermost web and a second innermost web, said first web spacedfrom said second web, said first web terminating in a first closureportion said second web terminating in a second closure portion, saidsecond closure element comprises a third outermost web and a fourthinnermost web, said third web spaced from said fourth web, said thirdweb terminating in a third closure portion which engages said firstclosure portion, said fourth web terminating in a fourth closure portionwhich engages said second closure portion; and wherein said first andthird outermost webs are compressed in regions of said steppeddefections.
 5. The invention as in claim 4 therein said first fasteningstrip includes a first wing and a second wing, said first wing and saidsecond wing are disposed outside of the space between said first web andsaid second web.
 6. The invention as in claim 4 wherein said firstclosure portion is a first male hook, said second closure portion is asecond male hook facing away from said first male hook, said thirdclosure portion is a first female hook, said fourth closure portion is asecond female hook facing toward said first female hook.
 7. Theinvention as in claim 6 wherein said first closure element includes afirst base, said first web and said second web are attached to saidfirst base, said second closure element includes a second base, saidthird web and said fourth web are attached to said second base.
 8. Theinvention as in claim 4 wherein said first fastening strip includes acolor different than said second fastening strip.
 9. The invention as inclaim 8 wherein at least a portion of one of said fastening strips istranslucent.
 10. The invention as in claim 8 wherein said firstfastening strip includes a first color and said second fastening stripincludes a second color and said fastening strips provide a third colorwhen said fastening strips are occluded.
 11. The invention as in claim 8wherein said second fastening strip includes a color change enhancementmember.
 12. The invention as in claim 11 wherein said color changeenhancement member is integrally associated with said second fasteningstrip.
 13. A closure device for a reclosable plastic bag comprising: afirst fastening strip; a second fastening strips arranged to beinterlocked over a predetermined longitudinal X axis with said firstfastening strip, said fastening strips have a transverse Y axis, saidtransverse Y axis is perpendicular to said longitudinal X axis, saidfastening strips have a vertical Z axis, said vertical Z axis isperpendicular to said longitudinal X axis, said vertical Z axis isperpendicular to said transverse Y axis, said first fastening stripcomprises a first web, said first web extending from said firstfastening strip, said first web terminating in a first closure portion,said second fastening strip comprises a second web, said second webextending from said second fastening strip, said second web terminatingin a second closure portion which engages said first closure portionwhen said fastening strips are occluded, said first and second closureportions having an occlusion and peel force; said first web including afirst series of intermittent peak and valley deformations disposed alongits longitudinal X axis, said first series of peak and valleydeformations each having a deformation component along the transverse Yaxis and a deformation component along the vertical Z axis; said secondweb including a second series of intermittent peak and valleydeformations disposed along its longitudinal X axis, said second seriesof peak and valley deformations each having a deformation componentalong the transverse Y axis and a deformation component along thevertical Z axis; and said second series of peak and valley deformationsbeing in substantially congruent and interdigitating relation with saidfirst series of peak and valley deformations when said first and secondfastening strips are interlocked such that said occlusion and peel forceis cycled intermittently over the length of the closure device.
 14. Theinvention as in claim 13 wherein: said first fastening strip includes athird web, said third web spaced from said first web, said third webincludes a third closure portion, said second fastening strip includes afourth web, said fourth web spaced from said second web, and said fourthweb includes a fourth closure portion which engages the third closureportion, said third web including a third series of intermittent peakand valley deformations disposed along its longitudinal X axis, saidthird series of peak and valley deformations each having a deformationcomponent along the transverse Y axis and a deformation component alongthe vertical Z axis; said fourth web including a fourth series ofintermittent peak and valley deformations disposed along itslongitudinal X axis, said fourth series of peak and valley deformationseach having a deformation component along the transverse Y axis and adeformation component along the vertical Z axis; and said fourth seriesof peak and valley deformations being in substantially congruent andinterdigitating relation with said third series of peak and valleydeformations when said first and second fastening strips are interlockedsuch that said occlusion and peel force is cycled intermittently overthe length of the closure device.
 15. The invention as in claim 14wherein said first fastening strip includes a first wing and a secondwing, said first wing and said second wing are disposed outside of thespace between said first web and said third web.
 16. The invention as inclaim 14 wherein said first closure portion is a first male hook, saidthird closure portion is a second male hook facing away from said firstmale hook, said second closure portion is a first female hook, saidfourth closure portion is a second female hook facing toward said firstfemale hook.
 17. The invention as in claim 13 wherein said firstfastening strip includes a color different than said second fasteningstrip.
 18. The invention as in claim 17 wherein at least a portion ofone of said fastening strips is translucent.
 19. The invention as inclaim 17 wherein said first fastening strip includes a first color andsaid second fastening strip includes a second color and said fasteningstrips provide a third color when said fastening strips arc occluded.20. The invention as in claim 17 wherein said second fastening stripincludes a color change enhancement member.
 21. The invention as inclaim 20 wherein said color change enhancement member is integrallyassociated with said second fastening strip.
 22. A closure device for areclosable plastic bag comprising: a first fastening strip; a secondfastening strip arranged to be interlocked over a predeterminedlongitudinal X axis with said first fastening strip, said fasteningstrips have a transverse Y axis, said transverse Y axis is perpendicularto said longitudinal X axis, said fastening strips have a vertical Zaxis, said vertical Z axis is perpendicular to said longitudinal X axis,said vertical Z axis is perpendicular to said transverse Y axis, saidfirst fastening strip comprises a first web, said first web extendingfrom said first fastening strip, said first web terminating in a firstclosure portion, said second fastening strip comprises a second web,said second web extending from said second fastening strip, said secondweb terminating in a second closure portion which engages said firstclosure portion when said fastening strips are occluded, said first andsecond closure portions having an occlusion and peel force; said firstweb including a first series of intermittent deformations disposed alongits longitudinal X axis wherein said first web is deflected upwardlyalong the vertical Z axis; said second web including a second series ofintermittent deformations disposed along its longitudinal X axis,wherein said second web is deflected upwardly along the vertical Z axis;and said second series of deformations being in substantially congruentand interdigitating relation with said first series deformations whensaid first and second fastening strips are interlocked such that saidocclusion and peel force is cycled intermittently over the length of theclosure device.
 23. The invention as in claim 22 wherein: said firstfastening strip includes a third web, said third web spaced from saidfirst web, said third web includes a third closure portion, said secondfastening strip includes a fourth web, said fourth web spaced from saidsecond web, and said fourth web includes a fourth closure portion whichengages the third closure portion; said third web including a thirdseries of intermittent deformations disposed along its longitudinal Xaxis, wherein said third web is deflected downwardly along the verticalZ axis; said fourth web including a fourth series of intermittentdeformations disposed along its longitudinal X axis, wherein said fourthweb is deflected downwardly along the vertical Z axis; and said fourthseries of deformations being in substantially congruent andinterdigitating relation with said third series of deformations whensaid first and second fastening strips are interlocked such that saidocclusion and peel force is cycled intermittently over the length of theclosure device.
 24. The invention as in claim 23 wherein said firstfastening strip includes a first wing and a second wing, said first wingand said second wing are disposed outside of the space between saidfirst web and said third web.
 25. The invention as in claim 23 whereinsaid first closure portion is a first male hook, said third closureportion is a second male hook facing away from said first male hook,said second closure portion is a first female hook, said fourth closureportion is a second female hook facing toward said first female hook.26. The invention as in claim 22 wherein said first fastening stripincludes a color different than said second fastening strip.
 27. Theinvention as in claim 26 wherein at least a portion of one of saidfastening strips is translucent.
 28. The invention as in claim 26wherein said first fastening strip includes a first color and saidsecond fastening strip includes a second color and said fastening snipsprovide a third color when said fastening strips are occluded.
 29. Theinvention as in claim 26 wherein said second fastening strip includes acolor change enhancement member.
 30. The invention as in claim 29wherein said color change enhancement member is integrally associatedwith said second fastening strip.
 31. A closure device for a reclosableplastic bag comprising: a first fastening strip; a second fasteningstrip arranged to be interlocked over a predetermined longitudinal Xaxis with said first fastening strip, said fastening strips have atransverse Y axis, said transverse Y axis is perpendicular to saidlongitudinal X axis, said fastening strips have a vertical Z axis, saidvertical Z axis is perpendicular to said longitudinal X axis, saidvertical Z axis is perpendicular to said transverse Y axis, said firstfastening strip comprises a first closure element that extends from saidfirst fastening strip along the transverse Y axis, said second fasteningstrip comprises a second closure element that extends from said secondfastening strip along the transverse Y axis and which engages said firstclosure element when said fastening strips are occluded; said firstclosure element including a first series of intermittent deformationsdisposed along its longitudinal X axis, each of said first series ofdeformations having a deformation component along the transverse Y axisthereby defining areas of compression in the first closure element; saidsecond closure element including a second series of intermittentdeformations disposed along its longitudinal X axis, each of said secondseries of deformations having a deformation component along thetransverse Y axis thereby defining areas of compression in the secondclosure element; and said areas of compression of second series ofdeformations being in substantially congruent and interdigitatingrelation with said areas of compression of said first series ofdeformations when said first and second fastening strips areinterlocked, said closure device imparting a vibratory or bumpy feelperceptible to the touch as the closure elements are occluded.
 32. Aclosure device for a reclosable plastic bag comprising: a firstfastening strip; a second fastening strip arranged to be interlockedover a predetermined longitudinal X axis with said first fasteningstrip, said fastening strips have a transverse Y axis, said transverse Yaxis is perpendicular to said longitudinal X axis, said fastening stripshave a vertical Z axis, said vertical Z axis is perpendicular to saidlongitudinal X axis, said vertical Z axis is perpendicular to saidtransverse Y axis, said first fastening strip comprises a first closureelement that extends from said first fastening strip along thetransverse Y axis, said second fastening strip comprises a secondclosure element that extends from said second fastening strip along thetransverse Y axis and which engages said first closure element when saidfastening strips are occluded; said first closure element including afirst series of intermittent deformations disposed along itslongitudinal X axis, each of said first series of deformations having adeformation component along the transverse Y axis thereby defining areasof compression in the first closure element; said second closure elementincluding a second series of intermittent deformations disposed alongits longitudinal X axis, each of said second series of deformationshaving a deformation component along the transverse Y axis therebydefining areas of compression in the second closure element; and saidareas of compression of second series of deformations being insubstantially congruent and interdigitating relation with said areas ofcompression of said first series of deformations when said first andsecond fastening strips are interlocked, said closure device impartingaudible clicking sounds therealong as the closure elements are beingoccluded or deoccluded.